The present invention relates generally to an electronic lancing device. More particularly, the present invention relates to an electronic lancing device comprising an electronic circuit that controls the movement of the lancet, mounted on a floating voice coil (bobbin) over a stationary magnet in a metal housing.
Lancing devices are used for obtaining a body fluid such as capillary blood or interstitial fluid from various body sites. A typical user of a mechanical lancing device is a person in a program of self-blood glucose monitoring for treatment of diabetes. Generally, the user depresses a firing button on a lancing device at a selected puncture site to activate the lancing device to puncture the skin at the site. Once the skin has been punctured and the lancet retracts from the lancing site, a small amount of body fluid such as capillary blood or interstitial fluid forms on the skin at the puncture. The drop of body fluid on the surface of the skin at the puncture site is then applied to a test sensor.
A major problem many existing mechanical lancing devices face is the amount of pain experienced by the user of the device. Three significant reasons related to the lancing devices contribute to an increased amount of user pain. The lancets in many lancing devices undergo side-to-side vibration while moving to puncture the skin. This vibration can lead to an irregular puncture, causing unnecessary pain and discomfort to a user.
Another reason contributing to increased user pain associated with existing mechanical lancing devices is the repeated bouncing into and out of the skin that occurs upon insertion of the lancet into the puncture or lancing site. Typical mechanical lancing devices have been shown to penetrate the skin two to six times before the lancet stops oscillating.
A further reason for elevated user pain is the relatively slow speed at which the lancet travels into and from the skin and the period of time that the lancet remains inside the skin or xe2x80x9cdwell time.xe2x80x9d A slower speed of lancet puncture, a longer duration of dwell time inside the skin, and a slower speed of lancet retraction all augment the amount of pain that a user experiences.
Accordingly, there exists a need for a lancing device that reduces user pain by eliminating the lancet from bouncing into and out of the skin, eliminating or reducing the vibration of the lancet when fired into the puncture site, and increasing the speed at which the lancet enters in and retracts from the skin, and controlling the dwell time of the lancet inside the skin.
The present invention provides an electronic lancing device comprising a stationary magnet mounted in a metal shell. A free-floating bobbin with attached coil is disposed over the magnet. The reciprocating movement of the bobbin""s forward, reverse and dwell positions are precisely controlled by an electronic circuit.
It has been discovered that the use of a substantially free-standing voice coil within a lancing device in coordination and combination with a stationary magnet and electronic circuit renders a much improved lancing device. The minimal weight of the free standing voice coil and the attractive forces of the magnet allow the electronic circuit to maintain excellent control over the advancement and retraction of a lancet. When the electronic lancing device is initiated by a user, the electronic circuit within the electronic lancing device provides sufficient current through the voice coil such that the coil, bobbin and lancet are repulsed from the magnet and propelled into the puncture site. The electronic circuit subsequently reverses the current to supply sufficient attractive current through the voice coil such that the lancet is retracted from the puncture site and pulled toward the magnet within the housing of the electronic lancing device. The electronic circuit can also control the pause or dwell time between the advancement and the retraction of the bobbin and lancet.